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    White residue after solder mask develope!!!

    Hello, my name is Hieu. I'm a process engineer of PCB manufacturing company.

    We have an issue about white residue on pad. When we doing solder mask and run developer. We check again see the white residue.

    Anybody have an opinions about this issue ?

    Picture below
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    Re: White residue after solder mask develope!!!

    Hi,

    What exactly do you mean?

    Add some marks on the pictures.

    Klaus
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    Re: White residue after solder mask develope!!!

    I think they mean the uneven surface after plating, you can just see it against the gold. I suspect this is the underlying copper being uneven and the gold plating just makes it more obvious. Nothing to worry about.

    Brian.
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    Re: White residue after solder mask develope!!!

    Photo resolution is too low to see details. Would prefer a microscope photo with diffuse lighting.

    To me, the pad surface looks partly like silver metallic rather than white. What's the gold process? If it's nickel-gold, could it be that the final gold layer is damaged?

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    Re: White residue after solder mask develope!!!

    Hi Klaus

    as you can see, on the Annula Ring, we have some white residue, I mark on picture below. It's happen when we do solder mask -> exposure -> cure (enough time) -> develop soldermask -> test (we find the residue at this step.

    this residue some time can be cleaned by gently wiping, some time it's can not clean and we have to remove all the solder mask and do it again. Because this white residue, when we do next step (do reflow, it's cannot be welded).

    This is the terrible issue that we have met.

    Click image for larger version. 

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    Hieu

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    Re: White residue after solder mask develope!!!

    Quote Originally Posted by betwixt View Post
    I think they mean the uneven surface after plating, you can just see it against the gold. I suspect this is the underlying copper being uneven and the gold plating just makes it more obvious. Nothing to worry about.

    Brian.
    Hi Brian

    it's not the problem with the plating. As i noted above. I send you picture with a mark, picture below. You can see it's has a white residue on annular ring. The process is : Clean acid -> do Solder mask -> exposure -> cure (enough heat and times) -> develop -> test (we find the white residue at this step).

    It's very serious. because if we have this white residue, when we do next step we can not do reflow, can not be welded.

    Hieu

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    Re: White residue after solder mask develope!!!

    Quote Originally Posted by FvM View Post
    Photo resolution is too low to see details. Would prefer a microscope photo with diffuse lighting.

    To me, the pad surface looks partly like silver metallic rather than white. What's the gold process? If it's nickel-gold, could it be that the final gold layer is damaged?
    Hi FvM

    Thank you for your reply. Sorry with the picture, I think it's clear enough to see the white residue. I send a picture with a mark, picture below. It's not from plating, we have no damaged with the gold plating.

    the process is : Clean with acid -> do solder mask -> exposure -> cure (with enough heat and times) -> develop -> test (we found the white residue at this step)

    this is the serious issue. Because if we have the white residue we can not do the next step ( reflow.. it's cannot be welded).

    Click image for larger version. 

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    Hieu

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    Re: White residue after solder mask develope!!!

    Quote Originally Posted by betwixt View Post
    I think they mean the uneven surface after plating, you can just see it against the gold. I suspect this is the underlying copper being uneven and the gold plating just makes it more obvious. Nothing to worry about.

    Brian.
    Click image for larger version. 

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    picture with the mark. thank your reply

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    Re: White residue after solder mask develope!!!

    I think it's clear enough to see the white residue.
    Not at all, I fear.

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    Re: White residue after solder mask develope!!!

    Hi,

    Not at all, I fear.
    I have to agree.

    I see a bright - almost white part at the hole --- I think this just is the reflection of the light.

    Klaus
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    Re: White residue after solder mask develope!!!

    Quote Originally Posted by KlausST View Post
    Hi,


    I have to agree.

    I see a bright - almost white part at the hole --- I think this just is the reflection of the light.

    Klaus
    We have many many prolem with this white residue
    it's not a bright
    You can see, that white color on the annular ring. That the white residue.

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  12. #12
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    Re: White residue after solder mask develope!!!

    Quote Originally Posted by FvM View Post
    Not at all, I fear.
    Sorry again about the picture
    But we have many many problem with this white residue . You can see, that white color on the annular ring. That the white residue.

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